Band clamp with multiple upsilon-restrainer means



July 30, 1957 A. D. HERMAN ETAL 2,801,116

BAND CLAMP WITH MULTIPLE V-RESTRAINER MEANS Filed July 18, 1955 A. DALEHERMAN a mzoooms A. wooLsE Y,

INVENTORS.

A 7' TORNE Y.

Unite Patented July 30, 1957 BAND CLAMP WITH MULTIPLE V-RESTRAINER MEANSAlbert D. Herman, Encino, and Theodore A. Woolsey, Pasadena, Calif,assignors, by mesne assignments, to Aeroquip Corporation, .Fackson, liiichn, a corporation of Michigan Application July 13, 1955, Serial No.522,743

6 Claims. or. 285-365} This invention relates to band clamps of the typeused in coupling together a pair of flanged parts such as the sectionsof a tubing line. Such a clamp customarily embodies opposed jaw membersfor embracing engagement with flanges that are to be coupled together, aconstrictor band encircling the jaw members, and connector parts fordrawing the ends of the band together. Ordinarily, the jaw membersembody opposed jaws that diverge toward the axis of the clamp, forexerting wedging action against the coupling flanges, whereby axialpressure may be applied to the flanges to seal them tightly against oneanother or against an interposed gasket or seal ring. In a common typeof such band clamp, the jaw members are in the form of arcuatelyelongated channel sections, a common method of fabricating them being byyoder roll forming from ribbon metal and cutting the rolled coil intoselected lengths.

A general object of the present invention is to provide a coupling clampwhich does not require the use of the elongated arcuate channelsections, and which correspondingly dispenses with the necessity forrolling or other comparably diflicult and expensive forming operation.

A specific object is to provide a coupling clamp embodying jaw elementswhich may be fabricated easily and inexpensively on a high speed punchpress in a simple die-blanking operation.

A further object is to provide an improved method of fabricating acoupling clamp of the general type referred to above.

One of the problems encountered in coupling clamps is the load limitwhich can be endured by the opposed wedging jaws without spreading. Inthe common type of coupling clamp referred to above, the axial loadlimit is determined by the thickness of the ribbon metal from which theelongated jaw sections are fabricated. To adapt the manufacture of suchclamps to a large number of varying load requirements, necessitates theselection and utilization of an equal number of thickness gages in theribbon metal stock (other factors being the same) if maximum efliciencyin the use of material for each load requirement, is to be attained.Since it is feasible from a manufacturing standpoint to stock andfabricate only a limited selection of combinations of material, widthand thickness in the ribbon or sheet metal stock from which thecouplings are fabricated, in actual practice there is dictated acompromise wherein a selected ribbon stock must serve a range of loadrequirements, and a coupling in the lower end of such range will thusutilize jaw sections that are thicker and heavier than actuallyrequired.

Where coupling clamps of the general type under consideration areutilized in aircraft, elimination of excess weight, even though inslight amounts, is quite an important consideration. One of the majorobjects of the present invention is to provide a coupling clamp of anovel construction such that the weight of the clamp can be adjusted tovary with load requirements so as to minimize weight over a verysubstantial range, without the multiplication of tooling or stock sizes.More specifically, the invention contemplates the provision of acoupling clamp utilizing jaw segments such that the weight of the clampcan be adjusted to load requirements simply by varying the number ofsegments utilized in the clamp, and yet wherein uniformity ofcircumferential spacing of the jaw segments (for uniform application ofclamping pressure around the circumference of the clamp) is attainedregardless of the number of segments utilized.

In the common form of coupling clamps utilizing the simple V-sectionchannel, the resistance of the jaws to spreading is determined by thestrength of the metal in the bends at the bottom of the channel, wherethe spreading couples are applied at maximum intensity. Improvements inthe strength-weight ratio can be gained by t ussing construction which,however, increases the expense of fabrication by complicating therolling or other forming of the channel sections, and requiring weldingfor the most eflicient trussing. An important object of the pres entinvention is to provide a coupling clamp utilizing jaw segments of fullytrussed, integral closed loop form, in a relatively inexpensive, easilyfabricated part requiring no welding operation.

A still further object is to provide a coupling clamp utilizing jawsegments which, for the purpose of attaining maximum ratio of jawstrength to weight, can be processed to uniform hardness and toughnessthroughout, avoiding the problems of hardness and strength variationsarising from work hardening which takes place in the forming of sheetmetal.

Another object is to provide a coupling clamp wherein uniformdistribution of radial and axial loads between jaw segments is attainedby virtue of self alignment of the jaw segments with relation to theflanges being coupled, whereby all jaw segments are caused to operate atmaximum efiiciency, and whereby failures arising from overloading of onepart of a coupling while another part is underloaded, are avoided.

Other objects will become apparent in the ensuing specifications andappended drawing in which:

Fig. 1 is an exploded perspective view of a tubing joint includingflanges, tube sections and a coupling clamp embodying my invention;

Fig. 2 is an axial sectional view through such joint;

Fig. 3 is a detail perspective view of a fragmentary portion of theclamp;

Fig. 4 is a fragmentary sectional view of a modified form of the clamp;

Fig. 5 is a fragmentary sectional view of another modified form of theclamp;

Fig. 6 is a side view of a portion of anot er modified form of theclamp;

Fig. 7 is a perspective view of the jaw segment of Fig. 6;

Fig. 8 is a side view of another modified form of the invention; and

Fig. 9 is a perspective view of the jaw segment of Fig. 8.

THE INVENTZON AS DISCLOSED IN FIGS. 1-3

The preferred form Referring now specifically to the form of theinvention shown in Figs. 1, 2 and 3, I have illustrated therein, as anexample of a preferred form in which the invention may be embodied, acoupling clamp, indicated generally at A, for coupling together a pairof adjoining tube flanges, indicated generally by the referencecharacter B. Merely by way of illustration of what may be regarded as aconventionel tube flange structure, we have shown in Fig. 2, tubesections 10 and 10 having respective flanges 11, 11' which are providedwith spaced grooves to receive a gasket or seal ring 12 for establishinga fluid tight joint between the tube sections. The outer faces offlanges 11, 11 may be frusto-conical as shown, for cooperation withinclined'wedging'faces of the opposed jaws 13 of jaw segments a. Thewedging faces of the series :of segments collectively define opposed,approximately 'frusto conical faces of an interrupted channelcorresponding generally in shape to the flange contours. It will beapparent that radially inward movement of jaw segments a, underpressure, will provide a wedging action against flanges 11, 11' whichwill force them against gasket 12 to establish a pressure seal asrequired.

The invention is particularly characterized by the fact 7 jaw segments aare in the form of metal slabs, arranged with their minimum dimension(thickness) as their circumferential dimension and with their majordimensions (width and height), disposed in planes (indicated by the'broken lines 14 in Fig. 1) which radiate from the axis 15 of the clamp.Jaw segments a are carried by a constrictor band 16 of flexible ribbonmetal and are secured thereto with sufficient anchorage to be maintainedin the aforesaid radiating axial plane. This may be accomplished byproviding each segment with a transverse slot '17 in the head portion 18of each segment, and assembling the segments on band 16 with the latterextending through and snugly fitted in the respective slots 17, and

either welded to or clamped against the band 16 under suflicientpressure to resist dislodgement of the segments .relative to the bandunder the forces that are applied to the segments when the couplingclamp is drawn tightly around the flanges 11, 11'. it is preferred toresistance weld the head'18 of the segments to the band 16 so that thesegments become integrally united to the band along both lips of theslot 17.

The segments a are of 'slab form, i. e., in the form of flat, one-pieceblanks die cut from sheet or plate metal of appropriate thickness suchthat the segments have adequate'rigidity, suflicient width of anchorageto bands 16, and adequate strength in jaws 13 to resist spreading underthe reactive loads developed by the wedging engagement against tubeflanges 11, 11. For maximum ratio of strength to weight, the jaws 13 areof truss form, including diagonal bars 20 the inner faces of whichconstitute the wedging faces of the jaws, and including trussing struts21, which are parallel, normal to the edge of head 18, disposed so as todefine the side margins of the segments, and integrally join the remoteends of jaw'bars 24) to head 18. The near ends of bars 20 are integrallyjoined to the center of head 18. Triangular cut-out spaces 22 aredefined between the bars 20, struts 21 and head 18. The elimination ofmetal from spacer ZZ'substantially lightens the segments withoutnoticeably weakening them. With the'above described construction, theoverall contour of the segments may be generally that of a square with acentral, truncated V-shaped notch 23 in one side, defined between bars20.

-with the respective lips (longitudinal faces) of slots17, 7

For maximum anchorage, H

The segments a are substantially uniformly spaced around thecircumference of band 16, the extent of spacing and the number ofsegments being varied in accordance with the load requirement of theclamp. In gen eral, the clamp embodies a fairly large number ofsegments, there being a multiple number of segments for each quadrant ofthe coupling and, in the average clamp, these segments being spaced notover about 15 arcuate displacement apart. In theexample shown, thespacing is approximately 10- angular separation. In some applications,the spacing might be considerably closer and in of clamps, differingfrom one another by the addition or subtraction of one segment, wherebya fairly exact fitting of the clamp to each load requirement within arange of only moderately varying requirement figures, may be simply andeasily attained without in. any way complicating the toolingor'fabricating requirement. For filling quantity orders, it may bedesirable to provide separate tooling for each particular clamp, in theform of a jig for locating the segments accurately in, their uniformlyspaced relation, in accordance with requirements of the particularclamp. Such a jig, however, is not expensive and does not add a greatdeal to the overall tooling expense.

THE MODIFIED FORM OF THE INVENTION SHOWN IN FIG. 4

=' faces of the segments against these radial edges of the :clip 25.Stated somewhat difierently,,the'clips 25 may function to block thesegments apart in uniformly spaced positions and to simultaneously blockthem against tilting.

Operation V In the operation of the clamp, it is wrapped around theflanges 11,11, like a necklace, and its ends are'brought together'andconnected by a conventional latching takeup connector 24 of any suitableknown type, through "which circumferential tension may be applied to theclamp by drawing the ends thereof toward one another. As the segmentsbecome tightened against flanges 11, 11' their legs 13 will exert awedging action thereagainst to draw the flanges into sealing engagementwith gasket 12. At the same time, the circumferential shortening of theclamp will necessitate some sliding of the segments circumferentiallyagainst flangesll, 1 1'. The anchorage of the segments to the band 16must be sutficiently secure to resist the tendency to tilt away fromrespective radiating planes, in response to the drag created asanincident to said shortening. V

Should the frusto-conical outer faces of flanges 11, 11' vary from truefrusto-conical form the segments a will automatically conform to theirregularities, the slight displacements of the segments from theirnormal positions cal flange faces as the clamp is tightened.

Fig. 1 shows appproximately a minimum number of segments, such aswould'be suitable for joining the sections of a low-pressure fluid line. Asprogressively greater loads are encountered, an increasing number ofsegments may be added, until, for extremely high loads, the

number of segments might be trebled or quadrupled over .the'number shownin Fig. l. Thus a wide variety of load conditions can be satisfactorilymet with a coupling having just enough segments to handle the load ineach case, and therefore having minimum weight for the givenrequirements. Yet the segments may be identical in each instance, andtooling costs are not multiplied with the multiplication of segmentcombinations.

, THE INVENTION AS DISCLOSED IN FIG. 5

Fig. 5 illustrates how a spacer collar 25b may be formed integrally witha jaw segment 12, by partially detaching a pair of tabs from a portion27 'of segment head 18b, which portion 27 is bent to define, with thebody of segment [2, a right dihedral angle. The collar 25a may beclamped tightly against band 16, without welding, to securely positionthe segment circumferentially of the band, and provides leverage toresist the load couples tending to tilt the segment when the coupling isbeing drawn tightly around a pair of flanges. Alternatively, the collar25a or head portion 27 may be spot welded or riveted to band 16.

THE INVENTION AS DISCLOSED IN FIG. 9

Fig. 9 illustrates a segment 0 similar to that of Fig. 5, but somewhatsimpler in that it omits the collar 25a and has a bent head portion 270of plain rectangular form which may be spot welded, as at 30, or rivetedto a band 16, extending through a slot 170 the upper margin of whichlies in the plane of the under face of head portion 270. A series of thesegments 0 may be arranged with their head portions all projecting inthe same direction, as indicated in Fig. 9. The head portions 270 thusfunction as spacers.

THE INVENTION AS DISCLOSED IN FIG. 8

As shown in Fig. 8, two of the segments c may be attached, back-to-backto form double segments cc. To this end, the legs 13:: may bespot-Welded together, as indicated at 32, and the head portions 270,projecting circumferentially in opposite directions, may be spot weldedto band 16 at 30, the band projecting through the registering slots 17c.Alternatively, the head portions may be abutted as in Fig. 6, torestrain the segments from circumferential slippage on the band, thuseliminating the need for the welded connections 30.

THE INVENTION AS DISCLOSED IN FIGS. 6 AND 7 Fig. 7 discloses a jawsegment similar to the double segment cc of Fig. 8, but made from asingle blank of sheet metal, with the ends of legs 13d connected byintegral folds 33. Head portions 27a, bent in opposite directions into acommon plane at substantially right angles to the plane of the segmentbody, are adapted to lie flatly against the outer face of a band 16,extending through slots 17d in the respective head portions 18d of thesegment. The head portions may be bent somewhat beyond a right anglebend so as to define a dihedral angle of somewhat less than 90, and,when the segments are assembled on the band and the band is placed undertension, will be deflected outwardly and thereby tensionloaded so as tobear tightly against the band. The extremities of adjoining headportions 27d may be abutted as shown in Fig. 6, so as to brace thesegments one against another, locking them in circumferentially fixedpositions without requiring any welded or riveted connection between thesegments and the band. Likewise, no welded or riveted connection betweenthe halves of a segment body, is required. The double bracing action ofthe oppositely projecting head portions of a segment, against the outerface of band 16, coupled with the engagement of the inner margins ofslots 17d against the inner face of the band, thoroughly braces thesegments against tilting in response to couples set up in the drawing ofthe coupling tightly around a pair of flanges.

We claim:

1. In a coupling clamp: a constrictor band of ribbon metal; connectormeans for drawing the ends of the band together; and a plurality of jawsegments of stamped sheet metal attached to said band incircumferentially spaced succession, each segment being of L-form,including a body yoke disposed in a plane of the coupling axis andextending radially inwardly from said band and a head projectingcircumferentially from said yoke and bearing against the outer face ofsaid band, said body yoke comprising axially opposed flange-embracingjaws and a web bridging said jaws, said jaw segment having a slotdefined between said web and said head and snugly receiving said band,and said segment including rightangle bends at respective ends of saidslot, joining said head integrally to said web.

2. A coupling clamp as defined in claim 1, including a series of saidsegments arranged with said heads projecting in a common directioncircumferentially, each head at its end engaging the bends of theadjacent segment and thereby functioning as a spacer.

3. A clamp as defined in claim 1, wherein said head has integral tabsbent around the side margins of the band and engaged beneath the band.

4. A clamp as defined in claim 1, wherein said head is welded to theouter face of the band.

5. A clamp as defined in claim 1, wherein the segments are arranged inpairs with the yokes of each pair being in back-to-back abuttingengagement with the heads of the pair projecting circumferentially inopposite directions therefrom, whereby the yokes of the pair will braceone another against tilting under circumferential drag developed indrawings the coupling tight around a pair of tube flanges.

6. A clamp as defined in claim 1, wherein the segments are arranged inpairs with the yokes of each pair being in back-to-back abuttingengagement and with the heads of the pair projecting circumferentiallyin opposite directions therefrom, and including return bends whereby theinner ends of the abutting jaws of a pair of segments are integrallyjoined to one another, whereby the yokes of the pair will brace oneanother against tilting under circumferential drag developed in drawingthe coupling tight around a pair of flanges.

References Cited in the file of this patent UNITED STATES PATENTS2,353,572 Kuster July 11, 1944 2,513,067 Stephan June 27, 1950 2,675,253Stade Apr. 13, 1954 FOREIGN PATENTS 126,655 Great Britain May 22, 1919

